A Taxonomy of Operational Cyber Security Risks

A Taxonomy of Operational Cyber Security Risks James J. Cebula Lisa R. Young December 2010 TECHNICAL NOTE CMU/SEI-2010-TN-028 CERT Program Unlimited distribution subject to the copyright. http://www.sei.cmu.edu

This report was prepared for the SEI Administrative Agent ESC/XPK 5 Eglin Street Hanscom AFB, MA 01731-2100 The ideas and findings in this report should not be construed as an official DoD position. It is published in the interest of scientific and technical information exchange. This work is sponsored by the U.S. Department of Defense. The Software Engineering Institute is a federally funded research and development center sponsored by the U.S. Department of Defense. Copyright 2010 Carnegie Mellon University. NO WARRANTY THIS CARNEGIE MELLON UNIVERSITY AND SOFTWARE ENGINEERING INSTITUTE MATERIAL IS FURNISHED ON AN "AS-IS" BASIS. CARNEGIE MELLON UNIVERSITY MAKES NO WARRANTIES OF ANY KIND, EITHER EXPRESSED OR IMPLIED, AS TO ANY MATTER INCLUDING, BUT NOT LIMITED TO, WARRANTY OF FITNESS FOR PURPOSE OR MERCHANTABILITY, EXCLUSIVITY, OR RESULTS OBTAINED FROM USE OF THE MATERIAL. CARNEGIE MELLON UNIVERSITY DOES NOT MAKE ANY WARRANTY OF ANY KIND WITH RESPECT TO FREEDOM FROM PATENT, TRADEMARK, OR COPYRIGHT INFRINGEMENT. Use of any trademarks in this report is not intended in any way to infringe on the rights of the trademark holder. Internal use. Permission to reproduce this document and to prepare derivative works from this document for internal use is granted, provided the copyright and "No Warranty" statements are included with all reproductions and derivative works. External use. This document may be reproduced in its entirety, without modification, and freely distributed in written or electronic form without requesting formal permission. Permission is required for any other external and/or commercial use. Requests for permission should be directed to the Software Engineering Institute at permission@sei.cmu.edu. This work was created in the performance of Federal Government Contract Number FA8721-05-C-0003 with Carnegie Mellon University for the operation of the Software Engineering Institute, a federally funded research and development center. The Government of the United States has a royalty-free government-purpose license to use, duplicate, or disclose the work, in whole or in part and in any manner, and to have or permit others to do so, for government purposes pursuant to the copyright license under the clause at 252.227-7013. For information about SEI publications, please visit the library on the SEI website (http://www.sei.cmu.edu/library).

Table of Contents Acknowledgements Abstract vii ix Introduction 1 Taxonomy of Operational Cyber Security Risks 2 Class 1 Actions of People 3 Subclass 1.1 Inadvertent 3 Subclass 1.2 Deliberate 4 Subclass 1.3 Inaction 4 Class 2 Systems and Technology Failures 4 Subclass 2.1 Hardware 4 Subclass 2.2 Software 5 Subclass 2.3 Systems 5 Class 3 Failed Internal Processes 5 Subclass 3.1 Process Design or Execution 5 Subclass 3.2 Process Controls 6 Subclass 3.3 Supporting Processes 6 Class 4 External Events 6 Subclass 4.1 Hazards 7 Subclass 4.2 Legal Issues 7 Subclass 4.3 Business Issues 7 Subclass 4.4 Service Dependencies 7 Harmonization with Other Risk Practices 9 FISMA 10 NIST Special Publications 10 SEI OCTAVE Threat Profiles 11 Conclusion 16 Appendix A: Mapping of NIST SP 800-53 Rev. 3 Controls to Selected Taxonomy Subclasses and Elements 17 Appendix B: Mapping of Selected Taxonomy Subclasses and Elements to NIST SP 800-53 Rev. 3 Controls 27 References 33 CMU/SEI-2010-TN-028 i

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List of Figures Figure 1: Relationships Among Assets, Business Processes, and Services [Caralli 2010a] 9 Figure 2: Protection, Sustainability, and Risk [Caralli 2010a] 10 Figure 3: OCTAVE Generic Threat Profile for Human Actors Using Network Access [Alberts 2001b]12 Figure 4: OCTAVE Generic Threat Profile for Human Actors Using Physical Access [Alberts 2001b]13 Figure 5: OCTAVE Generic Threat Profile for System Problems [Alberts 2001b] 14 Figure 6: OCTAVE Generic Threat Profile for Other Problems [Alberts 2001b] 15 CMU/SEI-2010-TN-028 iii

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List of Tables Table 1: Taxonomy of Operational Risk 3 Table 2: Mapping of NIST Control Families to Selected Taxonomy Subclasses and Elements 17 Table 3: Mapping of Taxonomy Subclasses and Elements to NIST Controls 27 CMU/SEI-2010-TN-028 v

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Acknowledgements We wish to acknowledge David Mundie, James Stevens, and Richard Caralli of the Software Engineering Institute s CERT Program for their thorough review and input to this document. CMU/SEI-2010-TN-028 vii

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Abstract This report presents a taxonomy of operational cyber security risks that attempts to identify and organize the sources of operational cyber security risk into four classes: (1) actions of people, (2) systems and technology failures, (3) failed internal processes, and (4) external events. Each class is broken down into subclasses, which are described by their elements. This report discusses the harmonization of the taxonomy with other risk and security activities, particularly those described by the Federal Information Security Management Act (FISMA), the National Institute of Standards and Technology (NIST) Special Publications, and the CERT Operationally Critical Threat, Asset, and Vulnerability Evaluation SM (OCTAVE ) method. CMU/SEI-2010-TN-028 ix

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Introduction Organizations of all sizes in both the public and private sectors are increasingly reliant on information and technology assets, supported by people and facility assets, to successfully execute business processes that, in turn, support the delivery of services. Failure of these assets has a direct, negative impact on the business processes they support. This, in turn, can cascade into an inability to deliver services, which ultimately impacts the organizational mission. Given these relationships, the management of risks to these assets is a key factor in positioning the organization for success. Operational cyber security risks are defined as operational risks to information and technology assets that have consequences affecting the confidentiality, availability, or integrity of information or information systems. This report presents a taxonomy of operational cyber security risks that attempts to identify and organize the sources of operational cyber security risk into four classes: (1) actions of people, (2) systems and technology failures, (3) failed internal processes, and (4) external events. Each class is broken down into subclasses, which are described by their elements. Operational risks are defined as those arising due to the actions of people, systems and technology failures, failed internal processes, and external events. The CERT Program, part of Carnegie Mellon University s Software Engineering Institute (SEI), developed these four classes of operational risk in the CERT Resilience Management Model [Caralli 2010b], which draws upon the definition of operational risk adopted by the banking sector in the Basel II framework [BIS 2006]. Within the cyber security space, the risk management focus is primarily on operational risks to information and technology assets. People and facility assets are also considered to the extent that they support information and technology assets. This taxonomy can be used as a tool to assist in the identification of all applicable operational cyber security risks in an organization. Toward that end, this report also discusses the harmonization of the taxonomy with other risk identification and analysis activities such as those described by the Federal Information Security Management Act of 2002 [FISMA 2002], security guidance contained within the National Institute of Standards and Technology (NIST) Special Publications series, and the threat profile concept contained within the CERT Operationally Critical Threat, Asset, and Vulnerability Evaluation SM (OCTAVE ) method. SM CERT and OCTAVE are registered marks owned by Carnegie Mellon University. Operationally Critical Threat, Asset, and Vulnerability Evaluation is a service mark of Carnegie Mellon University. CMU/SEI-2010-TN-028 1

Taxonomy of Operational Cyber Security Risks The taxonomy of operational cyber security risks, summarized in Table 1 and detailed in this section, is structured around a hierarchy of classes, subclasses, and elements. The taxonomy has four main classes: actions of people action, or lack of action, taken by people either deliberately or accidentally that impact cyber security systems and technology failures failure of hardware, software, and information systems failed internal processes problems in the internal business processes that impact the ability to implement, manage, and sustain cyber security, such as process design, execution, and control external events issues often outside the control of the organization, such as disasters, legal issues, business issues, and service provider dependencies Each of these four classes is further decomposed into subclasses, and each subclass is described by its elements. The structure of this taxonomy is derived from risk taxonomies previously developed by the SEI in the engineered systems operations [Gallagher 2005] and high-performance computing software development [Kendall 2007] subject areas. Additionally, this taxonomy complements the Department of Homeland Security (DHS) Risk Lexicon [DHS 2008] by describing instances of operational cyber security risks in greater detail. These risks are a small subset of the universe of risks of concern to DHS and covered by its lexicon. It is important to note that risks can cascade: risks in one class can trigger risks in another class. In this case, the analysis of a particular risk may involve several elements from different classes. For example, a software failure due to improper security settings could be caused by any of the elements of inadvertent or deliberate actions of people. CMU/SEI-2010-TN-028 2

Table 1: Taxonomy of Operational Risk 1. Actions of People 2. Systems and Technology Failures 1.1 Inadvertent 1.1.1 Mistakes 1.1.2 Errors 1.1.3 Omissions 1.2 Deliberate 1.2.1 Fraud 1.2.2 Sabotage 1.2.3 Theft 1.2.4 Vandalism 1.3 Inaction 1.3.1 Skills 1.3.2 Knowledge 1.3.3 Guidance 1.3.4 Availability 2.1 Hardware 2.1.1 Capacity 2.1.2 Performance 2.1.3 Maintenance 2.1.4 Obsolescence 2.2 Software 2.2.1 Compatibility 2.2.2 Configuration management 2.2.3 Change control 2.2.4 Security settings 2.2.5 Coding practices 2.2.6 Testing 2.3 Systems 2.3.1 Design 2.3.2 Specifications 2.3.3 Integration 2.3.4 Complexity 3. Failed Internal Processes 3.1 Process design or execution 3.1.1 Process flow 3.1.2 Process documentation 3.1.3 Roles and responsibilities 3.1.4 Notifications and alerts 3.1.5 Information flow 3.1.6 Escalation of issues 3.1.7 Service level agreements 3.1.8 Task hand-off 3.2 Process controls 3.2.1 Status monitoring 3.2.2 Metrics 3.2.3 Periodic review 3.2.4 Process ownership 3.3 Supporting processes 3.3.1 Staffing 3.3.2 Funding 3.3.3 Training and development 3.3.4 Procurement 4. External Events 4.1 Disasters 4.1.1 Weather event 4.1.2 Fire 4.1.3 Flood 4.1.4 Earthquake 4.1.5 Unrest 4.1.6 Pandemic 4.2 Legal issues 4.2.1 Regulatory compliance 4.2.2 Legislation 4.2.3 Litigation 4.3 Business issues 4.3.1 Supplier failure 4.3.2 Market conditions 4.3.3 Economic conditions 4.4 Service dependencies 4.4.1 Utilities 4.4.2 Emergency services 4.4.3 Fuel 4.4.4 Transportation Class 1 Actions of People Actions of people describes a class of operational risk characterized by problems caused by the action taken or not taken by individuals in a given situation. This class covers actions by both insiders and outsiders. Its supporting subclasses include inadvertent actions (generally by insiders), deliberate actions (by insiders or outsiders), and inaction (generally by insiders). Subclass 1.1 Inadvertent The inadvertent subclass refers to unintentional actions taken without malicious or harmful intent. Inadvertent actions are usually, though not exclusively, associated with an individual internal to the organization. This subclass is composed of the elements mistakes, errors, and omissions. 1.1.1 mistake individual with knowledge of the correct procedure accidentally taking incorrect action 1.1.2 error individual without knowledge of the correct procedure taking incorrect action 1.1.3 omission individual not taking a known correct action often due to hasty performance of a procedure CMU/SEI-2010-TN-028 3

Subclass 1.2 Deliberate The deliberate subclass of actions of people describes actions taken intentionally and with intent to do harm. This subclass is described by the elements fraud, sabotage, theft, and vandalism. Deliberate actions could be carried out by either insiders or outsiders. 1.2.1 fraud a deliberate action taken to benefit oneself or a collaborator at the expense of the organization 1.2.2 sabotage a deliberate action taken to cause a failure in an organizational asset or process, generally carried out against targeted key assets by someone possessing or with access to inside knowledge 1.2.3 theft the intentional, unauthorized taking of organizational assets, in particular information assets 1.2.4 vandalism the deliberate damaging of organizational assets, often at random Subclass 1.3 Inaction The inaction subclass describes a lack of action or failure to act upon a given situation. Elements of inaction include a failure to act because of a lack of appropriate skills, a lack of knowledge, a lack of guidance, and a lack of availability of the correct person to take action. 1.3.1 skills an individual s lack of ability to undertake the necessary action 1.3.2 knowledge an individual s ignorance of the need to take action 1.3.3 guidance a knowledgeable individual lacking the proper guidance or direction to act 1.3.4 availability the unavailability or nonexistence of the appropriate resource needed to carry out the action Class 2 Systems and Technology Failures Systems and technology failures describes a class of operational risk characterized by problematic abnormal or unexpected functioning of technology assets. Its supporting subclasses include failures of hardware, software, and integrated systems. Subclass 2.1 Hardware The hardware subclass addresses risks traceable to failures in physical equipment due to capacity, performance, maintenance, and obsolescence. 2.1.1 capacity inability to handle a given load or volume of information 2.1.2 performance inability to complete instructions or process information within acceptable parameters (speed, power consumption, heat load, etc.) 2.1.3 maintenance failure to perform required or recommended upkeep of the equipment 2.1.4 obsolescence operation of the equipment beyond its supported service life CMU/SEI-2010-TN-028 4

Subclass 2.2 Software The software subclass addresses risks stemming from software assets of all types, including programs, applications, and operating systems. The elements of software failures are compatibility, configuration management, change control, security settings, coding practices, and testing. 2.2.1 compatibility inability of two or more pieces of software to work together as expected 2.2.2 configuration management improper application and management of the appropriate settings and parameters for the intended use 2.2.3 change control changes made to the application or its configuration by a process lacking appropriate authorization, review, and rigor 2.2.4 security settings improper application of security settings, either too relaxed or too restrictive, within the program or application 2.2.5 coding practices failures due to programming errors, including syntax and logic problems and failure to follow secure coding practices 2.2.6 testing inadequate or atypical testing of the software application or configuration Subclass 2.3 Systems The systems subclass deals with failures of integrated systems to perform as expected. Systems failures are described by the elements design, specifications, integration, and complexity. 2.3.1 design improper fitness of the system for the intended application or use 2.3.2 specifications improper or inadequate definition of requirements or failure to adhere to the requirements during system construction 2.3.3 integration failure of various components of the system to function together or interface correctly; also includes inadequate testing of the system 2.3.4 complexity system intricacy or a large number or interrelationships between components Class 3 Failed Internal Processes Failed internal processes describes a class of operational risk associated with problematic failures of internal processes to perform as needed or expected. Its supporting subclasses include process design or execution, process controls, and supporting processes. Subclass 3.1 Process Design or Execution The process design or execution subclass deals with failures of processes to achieve their desired outcomes due to process design that is improper for the task or due to poor execution of a properly designed process. The elements of process design or execution are process flow, process documentation, roles and responsibilities, notifications and alerts, information flow, escalation of issues, service level agreements, and task hand-off. 3.1.1 process flow poor design of the movement of process outputs to their intended consumers 3.1.2 process documentation inadequate documentation of the process inputs, outputs, flow, and stakeholders CMU/SEI-2010-TN-028 5

3.1.3 roles and responsibilities insufficient definition and understanding of process stakeholder roles and responsibilities 3.1.4 notifications and alerts inadequate notification regarding a potential process problem or issue 3.1.5 information flow poor design of the movement of process information to interested parties and stakeholders 3.1.6 escalation of issues the inadequate or nonexistent ability to escalate abnormal or unexpected conditions for action by appropriate personnel 3.1.7 service level agreements the lack of agreement among process stakeholders on service expectations that causes a failure to complete expected actions 3.1.8 task hand-off dropping the ball due to the inefficient handing off of a task in progress from one responsible party to another Subclass 3.2 Process Controls The process controls subclass addresses process failures due to inadequate controls on the operation of the process. The elements of this subclass are status monitoring, metrics, periodic review, and process ownership. 3.2.1 status monitoring failure to review and respond to routine information about the operation of a process 3.2.2 metrics failure to review process measurements over time for the purpose of determining performance trends 3.2.3 periodic review failure to review the end-to-end operation of the process on a periodic basis and make any needed changes 3.2.4 process ownership failure of a process to deliver the expected outcome because of poor definition of its ownership or poor governance practices Subclass 3.3 Supporting Processes The supporting processes subclass deals with operational risks introduced due to failure of organizational supporting processes to deliver the appropriate resources. The supporting processes of concern are the elements staffing, accounting, training and development, and procurement. 3.3.1 staffing failure to provide appropriate human resources to support its operations 3.3.2 funding failure to provide appropriate financial resources to support its operations 3.3.3 training and development Failure to maintain the appropriate skills within the workforce 3.3.4 procurement failure to provide the proper purchased service and goods necessary to support operations Class 4 External Events External events describes a class of operational risk associated with events generally outside the organization s control. Often the timing or occurrence of such events cannot be planned or predicted. The supporting subclasses of this class include disasters, legal issues, business issues, and service dependencies. CMU/SEI-2010-TN-028 6

Subclass 4.1 Hazards The hazards subclass deals with risks owing to events, both natural and of human origin, over which the organization has no control and that can occur without notice. The elements supporting this subclass include weather event, fire, flood, earthquake, unrest, and pandemic. 4.1.1 weather event adverse weather situations such as rain, snow, tornado, or hurricane 4.1.2 fire fire within a facility or disruption caused by a fire external to a facility 4.1.3 flood flooding within a facility or disruption caused by a flood external to a facility 4.1.4 earthquake disruption of organizational operations due to an earthquake 4.1.5 unrest disruption of operations due to civil disorder, riot, or terrorist acts 4.1.6 pandemic widespread medical conditions that disrupt organizational operations Subclass 4.2 Legal Issues The legal issues subclass deals with risks potentially impacting the organization due to the elements regulatory compliance, legislation, and litigation. 4.2.1 regulatory compliance new governmental regulation or failure to comply with existing regulation 4.2.2 legislation new legislation that impacts the organization 4.2.3 litigation legal action taken against the organization by any stakeholder, including employees and customers Subclass 4.3 Business Issues The business issues subclass, described by the elements of supplier failure, market conditions, and economic conditions, deals with operational risks arising from changes in the business environment of the organization. 4.3.1 supplier failure the temporary or permanent inability of a supplier to deliver needed products or services to the organization 4.3.2 market conditions the diminished ability of the organization to sell its products and services in the market 4.3.3 economic conditions the inability of the organization to obtain needed funding for its operations Subclass 4.4 Service Dependencies The service dependencies subclass deals with risks arising from the organization s dependence on external parties to continue operations. The subclass is associated with the elements of utilities, emergency services, fuel, and transportation. 4.4.1 utilities failure of the organization s electric power supply, water supply, or telecommunications services 4.4.2 emergency services dependencies on public response services such as fire, police, and emergency medical services 4.4.3 fuel failure of external fuel supplies, for example to power a backup generator CMU/SEI-2010-TN-028 7

4.4.4 transportation failures in external transportation systems, for example, inability of employees to report to work and inability to make and receive deliveries CMU/SEI-2010-TN-028 8

Harmonization with Other Risk Practices The taxonomy can be used as a tool to help identify all applicable operational cyber security risks in an organization. To provide context and prioritize and manage these risks in a structured man- needs to be established. Assets are the basic units of value in the organization. There are four pri- ner, a basic understanding of the relationships among assets, business processes, and services mary types of assets: people, information, facilities, and technology. In the cyber security arena, the primary focus is on operational risks to information and technology assets, although people and facility assets are also considered. Assets are the building blocks of business processes. Busi- ness processes are the activities that support the organization s delivery of services. The relation- ships among assets, business processes, and services are shown in Figure 1. Figure 1: Relationships Among Assets, Business Processes, and Services [Caralli 2010a] Failure of these assets can have a direct, negative impact on the business processes that they sup- port. This, in turn, cascades into an inability to deliver services and ultimately impacts the mission of the organization. The taxonomy can assist in identifying operational risks in all four classes (actions of people, systems and technology failures, failed internal processes, and external events) to each of the four asset types. Risk management involves a balance between risk conditions (such as threats and vulnerabilities) and risk consequences. As part of a risk management strategy, protective and sustaining controls are applied to assets, as shown in Figure 2. CMU/SEI-2010-TN-028 9

Figure 2: Protection, Sustainability, and Risk [Caralli 2010a] Protective controls are intended to help manage risk conditions, while sustaining controls are intended to help manage risk consequences. In both cases, controls are applied at the asset level. FISMA The taxonomy provides a structured set of terms that covers all of the significant risk elements that could impact cyber security operations. The Federal Information Security Management Act of 2002 (FISMA), which applies to U.S. federal government agencies, provides a working definition of information security. This definition links the identified operational cyber security risks to specific examples of consequences impacting confidentiality, integrity, and availability. This is an important building block in the control selection and risk mitigation process. The FISMA definition of information security reads as follows: The term information security means protecting information and information systems from unauthorized access, use, disclosure, disruption, modification, or destruction in order to provide (A) integrity, which means guarding against improper information modification or destruction, and includes ensuring information non repudiation and authenticity; (B) confidentiality, which means preserving authorized restrictions on access and disclosure, including means for protecting personal privacy and proprietary information; and (C) availability, which means ensuring timely and reliable access to and use of information. NIST Special Publications In addition to providing the definition of information security described above, the FISMA legislation also tasked the National Institute of Standards and Technology (NIST) with developing information security guidelines for use by federal agencies. These guidelines are known as the CMU/SEI-2010-TN-028 10

NIST Special Publications (SP). Of particular interest is NIST SP 800-53 rev. 3 [NIST 2009], which provides a control catalog to be applied to federal information systems based on an analysis of the system s relative importance and consequence of loss. The controls specified in NIST SP 800-53 are primarily protective in nature and are applied tactically at the information-system level. In general, the controls specified in NIST SP 800-53 are at a lower level than the elements in the taxonomy. The taxonomy can be used as a tool to link the application of these controls into a broader risk management strategy. A mapping of the control catalog in NIST SP 800-53 rev. 3 to the risk subclasses identified in the taxonomy is provided in Appendix A. This appendix can be used to match NIST control families to types of operational cyber security risk. Appendix B provides the reverse: a mapping of taxonomy subclasses to the NIST SP 800-53 rev. 3 control catalog. Appendix B can be used to determine which NIST controls to consider in order to mitigate specific operational cyber security risks. SEI OCTAVE Threat Profiles The OCTAVE method, developed by the SEI [Alberts 2001a], provides a process for an organization to perform a comprehensive security risk evaluation. Phase 1 of the OCTAVE method uses the concept of asset-based threat profiles [Alberts 2001b]. While it is not the intent of this report to provide a detailed discussion of OCTAVE, the threat profiles are introduced here as a useful, graphical vehicle to link assets to risks and consequences, in-line with the definition of operational security risks. OCTAVE uses four standard threat categories: (1) human actors using network access, (2) human actors using physical access, (3) system problems, and (4) other problems. These generic categories can easily be extended or tailored to suit the particular need. In general, the threat categories from OCTAVE align with the classes in the risk taxonomy as follows: humans with network access actions of people class humans with physical access actions of people class system problems systems and technology failures class other problems failed internal processes and external events classes The threat profiles are represented graphically in a tree structure. Figure 3 through Figure 6 below illustrate the OCTAVE generic threat profiles for the four threat categories. The taxonomy and the techniques described in OCTAVE can serve as cross-checks to each other to ensure coverage of all classes of operational cyber security risk. CMU/SEI-2010-TN-028 11

Figure 3: OCTAVE Generic Threat Profile for Human Actors Using Network Access [Alberts 2001b] CMU/SEI-2010-TN-028 12

Figure 4: OCTAVE Generic Threat Profile for Human Actors Using Physical Access [Alberts 2001b] CMU/SEI-2010-TN-028 13

Figure 5: OCTAVE Generic Threat Profile for System Problems [Alberts 2001b] CMU/SEI-2010-TN-028 14

Figure 6: OCTAVE Generic Threat Profile for Other Problems [Alberts 2001b] CMU/SEI-2010-TN-028 15

Conclusion This report presents a taxonomy of operational cyber security risks and also discusses the relationship of the taxonomy to other risk and security activities. The taxonomy organizes the definition of operational risk into the following four classes: (1) actions of people, (2) systems and technology failures, (3) failed internal processes, and (4) external events. Each of these four classes is further decomposed into subclasses and elements. Operational cyber security risks are defined as operational risks to information and technology assets that have consequences affecting the confidentiality, availability, and integrity of information and information systems. The relationship of operational risks to consequences is discussed in the context of FISMA, the NIST Special Publications, and the OCTAVE method. We anticipate that revisions to the taxonomy will be necessary to account for changes in the cyber risk landscape. The present taxonomy is being validated through fieldwork with organizations under varying levels of regulatory compliance obligation and risk tolerance. The results of this fieldwork will inform taxonomy revisions. CMU/SEI-2010-TN-028 16

Appendix A: Mapping of NIST SP 800-53 Rev. 3 Controls to Selected Taxonomy Subclasses and Elements Table 2 can be used to match NIST control families to types of operational cyber security risk. References to taxonomy subclasses and elements refer to the numbering scheme shown in Table 1 and the body of this report. For example, item 1.1 refers to the subclass inadvertent actions of people (all elements apply), and item 2.2.2 refers to the configuration management element of systems and technology failures software. Table 2: Mapping of NIST Control Families to Selected Taxonomy Subclasses and Elements NIST SP 800-53 Rev. 3 Taxonomy Subclasses and Elements Control Number Control Description AC-1 Access Control Policy and Procedures 3.1 AC-2 Account Management 1.1, 1.2, 2.2.2, 2.2.3 AC-3 Access Enforcement 1.1, 2.2, 2.3 AC-4 Information Flow Enforcement 1.1, 2.2, 2.3 AC-5 Separation of Duties 1.1, 1.2, 2.2.2, 2.2.3, 2.2.4, 2.3.2, 3.1, 3.2 AC-6 Least Privilege 1.1, 1.2, 2.2.2, 2.2.3, 2.2.4, 2.3.2, 3.1, 3.2 AC-7 Unsuccessful Login Attempts 2.2, 2.3 AC-8 System Use Notification 2.2, 2.3 AC-9 Previous Logon (Access) Notification 2.2, 2.3 AC-10 Concurrent Session Control 2.2, 2.3 AC-11 Session Lock 2.2, 2.3 AC-12 Withdrawn N/A AC-13 Withdrawn N/A AC-14 Permitted Actions Without Identification or Authentication 2.2, 3.1 AC-15 Withdrawn N/A AC-16 Security Elements 1.1, 1.2, 2.3, 3.1 AC-17 Remote Access 1.2, 2.1, 2.2, 3.1, 3.2 CMU/SEI-2010-TN-028 17

NIST SP 800-53 Rev. 3 Taxonomy Subclasses and Elements Control Number Control Description AC-18 Wireless Access 1.2, 2.1, 2.2, 3.1, 3.2 AC-19 Access Control for Mobile Devices 1.1, 1.2, 2.1, 2.2, 3.1, 4.2 AC-20 Use of External Information Systems 1.1, 1.2, 3.1, 3.3.4, 4.3 AC-21 User-Based Collaboration and Information Sharing 1.1, 1.2, 3.1, 3.2, 3.3.3 AC-22 Publicly Accessible Content 1.1, 1;2, 3.1, 3.3.3 AT-1 Security Awareness and Training Policy and Procedures 3.1, 3.3.3 AT-2 Security Awareness 1.3.2, 1.3.3, 3.1, 3.3.3 AT-3 Security Training 1.3.1, 1.3.3, 3.1, 3.3.3, 4.1 AT-4 Security Training Records 1.2, 3.1, 3.3.3 AT-5 AU-1 Contacts with Security Groups and Associations Audit and Accountability Policy and Procedures 1.3.1, 1.3.2 1.1, 1.2, 3.2, 4.2.1, 4.2.2 AU-2 Auditable Events 1.1, 1.2, 3.1, 3.2, 4.2.1, 4.2.2 AU-3 Content of Audit Records 1.1, 1.2, 3.1, 3.2 AU-4 Audit Storage Capacity 2.1.1 AU-5 Response to Audit Processing Failures 1.1, 1.2, 3.2 AU-6 Audit Review, Analysis, and Reporting 3.2 AU-7 Audit Reduction and Report Generation 2.2, 2.3, 3.1 AU-8 Time Stamps 2.2, 2.3 AU-9 Protection of Audit Information 1.1, 1.2, 2.2, 2.3, 3.1, 3.2 AU-10 Non-Repudiation 1.1, 1.2, 2.2, 2.3, 3.2 AU-11 Audit Record Retention 3.1, 3.2 AU-12 Audit Generation 2.2, 2.3, 3.1 CMU/SEI-2010-TN-028 18

NIST SP 800-53 Rev. 3 Taxonomy Subclasses and Elements Control Number Control Description AU-13 Monitoring for Information Disclosure 3.1, 3.2, 4.2 AU-14 Session Audit 2.2, 2.3 CA-1 Security Assessment and Authorization Policies and Procedures 1.1, 1.2, 3.1, 3.2 CA-2 Security Assessments 1.1, 1.2, 3.1, 3.2 CA-3 Information System Connections 1.1, 1.2, 3.1 CA-4 Withdrawn N/A CA-5 Plan of Action and Milestones 1.3, 2.2, 3.1, 3.2, 3.3 CA-6 Security Authorization 3.1, 3.2 CA-7 Continuous Monitoring 2.2, 2.3, 3.2 CM-1 Configuration Management Policy and Procedures 2.2.2, 2.2.3, 2.2.4, 3.1, 3.2 CM-2 Baseline Configuration 2.2.2, 2.2.3, 2.2.4, 3.1, 3.2 CM-3 Configuration Change Control 2.2.2, 2.2.3, 2.2.4, 3.1, 3.2 CM-4 Security Impact Analysis 2.2.2, 2.2.3, 2.2.4, 2.2.5, 3.1 CM-5 Access Restrictions for Change 1.1, 1.2, 2.2.2, 2.2.3, 2.2.4, 2.2.5, 3.1 CM-6 Configuration Settings 2.2.2, 2.2.3, 2.2.4, 3.1, 3.2 CM-7 Least Functionality 1.1, 1.2, 2.2, 2.3, 3.1, 3.2 CM-8 Information System Component Inventory 2.1, 2.2, 2.3, 3.1 CM-9 Configuration Management Plan 2.2.2, 2.3 CP-1 Contingency Planning Policy and Procedures 3.1, 3.2, 4.1, 4.3, 4.4 CP-2 Contingency Plan 1.2, 1.3, 3.3, 4.1, 4.2, 4.3, 4.4 CP-3 Contingency Training 1.3, 3.3.3, 4.1, 4.4 CP-4 Contingency Plan Testing and Exercises 1.3, 3.1, 3.3.3, 4.1, 4.2, 4.3, 4.4 CP-5 Withdrawn N/A CMU/SEI-2010-TN-028 19

NIST SP 800-53 Rev. 3 Taxonomy Subclasses and Elements Control Number Control Description CP-6 Alternate Storage Site 2.1, 2.2, 4.1, 4.3 CP-7 Alternate Processing Site 2.1, 2.2, 2.3, 4.1, 4.4 CP-8 Telecommunications Services 2.2, 2.3, 3.3, 4.1, 4.2, 4.3 CP-9 Information System Backup 2.2, 2.3, 3.1 CP-10 IA-1 IA-2 Information System Recovery and Reconstitution Identification and Authentication Policy and Procedures Identification and Authentication (Organizational Users) 3.1, 4.1, 4.2, 4.3 1.1, 1.2, 2.2, 2.3, 3.1 1.1, 1.2, 2.2, 2.3, 3.1, 3.2 IA-3 Device Identification and Authentication 1.1, 1.2, 2.1, 2.3, 3.1, 3.2 IA-4 Identifier Management 1.1, 1.2, 2.2, 2.3, 3.1, 3.2 IA-5 Authenticator Management 1.1, 1.2, 2.2, 2.3, 3.1, 3.2 IA-6 Authenticator Feedback 1.1, 1.2, 2.2, 2.3, 3.1, 3.2 IA-7 Cryptographic Module Authentication 1.1, 1.2, 2.2, 2.3, 3.1, 3.2 IA-8 Identification and Authentication (Non-Organizational Users) 1.1, 1.2, 2.2, 2.3, 3.1, 3.2, 4.2, 4.3 IR-1 Incident Response Policy and Procedures 1.1, 1.2, 1.3, 3.1, 3.2 IR-2 Incident Response Training 1.3, 3.3.3 IR-3 Incident Response Testing and Exercises 1.1, 1.2, 1.3, 3.1, 3.2 IR-4 Incident Handling 1.1, 1.2, 1.3, 3.1, 3.2 IR-5 Incident Monitoring 1.1, 1.2, 1.3, 3.1, 3.2 IR-6 Incident Reporting 1.1, 1.2, 1.3, 3.1, 3.2. 4.2 IR-7 Incident Response Assistance 1.1, 1.2, 1.3, 3.1, 3.2, 3.3.4 IR-8 Incident Response Plan 1.1, 1.2, 1.3, 3.1, 3.2 MA-1 System Maintenance Policy and Procedures 2.1.3, 2.3, 3.1, 3.2 CMU/SEI-2010-TN-028 20

NIST SP 800-53 Rev. 3 Taxonomy Subclasses and Elements Control Number Control Description MA-2 Controlled Maintenance 1.1, 1.3, 2.1.3, 2.3, 3.1, 3.2, 3.3 MA-3 Maintenance Tools 1.1, 1.3, 2.1.3, 2.3, 3.1, 3.2, 3.3 MA-4 Non-Local Maintenance 1.1, 1.3, 2.1.3, 2.3, 3.1, 3.2, 3.3 MA-5 Maintenance Personnel 1.1, 1.3, 2.1.3, 2.3, 3.1, 3.2, 3.3, 4.3 MA-6 Timely Maintenance 1.1, 1.3, 2.1.3, 2.3, 3.1, 3.2, 3.3 MP-1 Media Protection Policy and Procedures 1.1, 1.2, 2.1, 2.2, 3.1, 3.2, 4.2 MP-2 Media Access 1.1, 1.2, 2.1, 2.2, 3.1, 3.2, 4.2 MP-3 Media Marking 1.1, 1.2, 2.1, 2.2, 3.1, 3.2, 4.2 MP-4 Media Storage 1.1, 1.2, 2.1, 2.2, 3.1, 3.2, 4.2 MP-5 Media Transport 1.1, 1.2, 2.1, 2.2, 3.1, 3.2, 4.2 MP-6 Media Sanitization 1.1, 1.2, 2.1, 2.2, 3.1, 3.2, 4.2 PE-1 Physical and Environmental Protection Policy and Procedures 1.1, 1.2, 2.1, 3.1, 3.2 PE-2 Physical Access Authorizations 1.1, 1.2, 2.1, 3.1, 3.2 PE-3 Physical Access Control 1.1, 1.2, 2.1, 3.1, 3.2 PE-4 Access Control for Transmission Medium 1.1, 1.2, 2.1, 3.1, 3.2 PE-5 Access Control for Output Devices 1.1, 1.2, 2.1, 3.1, 3.2 PE-6 Monitoring Physical Access 1.1, 1.2, 2.1, 3.1, 3.2 PE-7 Visitor Control 1.1, 1.2, 2.1, 3.1, 3.2 PE-8 Access Records 1.1, 1.2, 2.1, 3.1, 3.2 PE-9 Power Equipment and Power Cabling 1.1, 1.2, 2.1, 3.1, 3.2 PE-10 Emergency Shutoff 1.1, 1.2, 2.1, 3.1, 3.2, 4.1, 4.4 PE-11 Emergency Power 1.1, 1.2, 2.1, 3.1, 3.2, 4.1, 4.4 PE-12 Emergency Lighting 1.1, 1.2, 2.1, 3.1, 3.2, 4.1, 4.4 PE-13 Fire Protection 1.1, 1.2, 2.1, 3.1, 3.2, 4.1.2, 4.4 CMU/SEI-2010-TN-028 21

NIST SP 800-53 Rev. 3 Taxonomy Subclasses and Elements Control Number Control Description PE-14 Temperature and Humidity Controls 1.1, 1.2, 2.1, 3.1, 3.2 PE-15 Water Damage Protection 1.1, 1.2, 2.1, 3.1, 3.2, 4.1.3, 4.4 PE-16 Delivery and Removal 1.1, 1.2, 2.1, 3.1, 3.2, 4.1, 4.4 PE-17 Alternate Work Site 1.1, 1.2, 2.1, 3.1, 3.2, 4.1, 4.4 PE-18 Location of Information System Components 1.1, 1.2, 2.1, 3.1, 3.2, 4.1, 4.4 PE-19 Information Leakage 1.1, 1.2, 2.1, 3.1, 3.2, 4.2 PL-1 Security Planning Policy and Procedures 3.1, 3.2, 3.3 PL-2 System Security Plan 3.1, 3.2, 3.3 PL-3 Withdrawn N/A PL-4 Rules of Behavior 1.1, 1.2, 1.3, 3.3.3 PL-5 Privacy Impact Assessment 4.2, 4.3 PL-6 Security-Related Activity Planning 3.1, 3.2, 3.3 PS-1 Personnel Security Policy and Procedures 1.1, 1.2, 1.3, 3.3.3, 4.2 PS-2 Position Categorization 1.1, 1.2, 1.3, 3.3.3, 4.2 PS-3 Personnel Screening 1.1, 1.2, 1.3, 3.3.3, 4.2 PS-4 Personnel Termination 1.1, 1.2, 1.3, 3.3.3, 4.2 PS-5 Personnel Transfer 1.1, 1.2, 1.3, 3.3.3, 4.2 PS-6 Access Agreements 1.1, 1.2, 1.3, 3.3.3, 4.2 PS-7 Third-Party Personnel Security 1.1, 1.2, 1.3, 3.3.3, 4.3 PS-8 Personnel Sanctions 1.1, 1.2, 1.3, 3.3.3, 4.2 RA-1 Risk Assessment Policy and Procedures 3.1, 3.2 RA-2 Security Categorization 3.1, 3.2, 4.2, 4.3 RA-3 Risk Assessment 3.1, 3.2, 4.2, 4.3 RA-4 Withdrawn N/A RA-5 Vulnerability Scanning 1.1, 1.2, 1.3, 2.2.4, 3.1, 3.2 CMU/SEI-2010-TN-028 22

NIST SP 800-53 Rev. 3 Taxonomy Subclasses and Elements Control Number SA-1 Control Description System and Services Acquisition Policy and Procedures 2.3, 3.3.4, 4.4 SA-2 Allocation of Resources 2.1, 2.2, 2.3, 3.3, 4.2, 4.3 SA-3 Life Cycle Support 2.1, 2.2, 2.3, 3.3, 4.2, 4.3 SA-4 Acquisitions 2.3, 3.3.4, 4.4 SA-5 Information System Documentation 2.1, 2.2, 2.3, 3.3, 4.2, 4.3 SA-6 Software Usage Restrictions 2.1, 2.2, 2.3, 3.3, 4.2, 4.3 SA-7 User-Installed Software 2.1, 2.2, 2.3, 3.3, 4.2, 4.3 SA-8 Security Engineering Principles 2.1, 2.2, 2.3, 3.3, 4.2, 4.3 SA-9 External Information System Services 2.1, 2.2, 2.3, 3.3, 4.2, 4.3 SA-10 Developer Configuration Management 2.1, 2.2, 2.3, 3.3, 4.2, 4.3 SA-11 Developer Security Testing 2.1, 2.2, 2.3, 3.3, 4.2, 4.3 SA-12 Supply Chain Protections 2.1, 2.2, 2.3, 3.3, 4.2, 4.3 SA-13 Trustworthiness 2.1, 2.2, 2.3, 3.3, 4.2, 4.3 SA-14 Critical Information System Components 2.1, 2.2, 2.3, 3.3, 4.2, 4.3 SC-1 System and Communications Protection Policy and Procedures 1.1, 1.2, 2.1, 2.2, 2.3 SC-2 Application Partitioning 1.1, 1.2, 2.1, 2.2, 2.3 SC-3 Security Function Isolation 1.1, 1.2, 2.1, 2.2, 2.3 SC-4 Information in Shared Resources 1.1, 1.2, 2.1, 2.2, 2.3 SC-5 Denial of Service Protection 1.1, 1.2, 2.1, 2.2, 2.3 SC-6 Resource Priority 1.1, 1.2, 2.1, 2.2, 2.3 SC-7 Boundary Protection 1.1, 1.2, 2.1, 2.2, 2.3 SC-8 Transmission Integrity 1.1, 1.2, 2.1, 2.2, 2.3 SC-9 Transmission Confidentiality 1.1, 1.2, 2.1, 2.2, 2.3 SC-10 Network Disconnect 1.1, 1.2, 2.1, 2.2, 2.3 CMU/SEI-2010-TN-028 23

NIST SP 800-53 Rev. 3 Taxonomy Subclasses and Elements Control Number Control Description SC-11 Trusted Path 1.1, 1.2, 2.1, 2.2, 2.3 SC-12 Cryptographic Key Establishment and Management 1.1, 1.2, 2.1, 2.2, 2.3 SC-13 Use of Cryptography 1.1, 1.2, 2.1, 2.2, 2.3 SC-14 Public Access Protections 1.1, 1.2, 2.1, 2.2, 2.3 SC-15 Collaborative Computing Devices 1.1, 1.2, 2.1, 2.2, 2.3 SC-16 Transmission of Security Elements 1.1, 1.2, 2.1, 2.2, 2.3 SC-17 Public Key Infrastructure Certificates 1.1, 1.2, 2.1, 2.2, 2.3 SC-18 Mobile Code 1.1, 1.2, 2.1, 2.2, 2.3 SC-19 Voice Over Internet Protocol 1.1, 1.2, 2.1, 2.2, 2.3 SC-20 SC-21 SC-22 Secure Name/Address Resolution Service (Authoritative Source) Secure Name/Address Resolution Service (Recursive or Caching Resolver) Architecture and Provisioning for Name/Address Resolution Service 1.1, 1.2, 2.1, 2.2, 2.3 1.1, 1.2, 2.1, 2.2, 2.3 1.1, 1.2, 2.1, 2.2, 2.3 SC-23 Session Authenticity 1.1, 1.2, 2.1, 2.2, 2.3 SC-24 Fail in Known State 1.1, 1.2, 2.1, 2.2, 2.3 SC-25 Thin Nodes 1.1, 1.2, 2.1, 2.2, 2.3 SC-26 Honeypots 1.1, 1.2, 2.1, 2.2, 2.3 SC-27 Operating System-Independent Applications 1.1, 1.2, 2.1, 2.2, 2.3 SC-28 Protection of Information at Rest 1.1, 1.2, 2.1, 2.2, 2.3 SC-29 Heterogeneity 1.1, 1.2, 2.1, 2.2, 2.3 SC-30 Virtualization Techniques 1.1, 1.2, 2.1, 2.2, 2.3 SC-31 Covert Channel Analysis 1.1, 1.2, 2.1, 2.2, 2.3 SC-32 Information System Partitioning 1.1, 1.2, 2.1, 2.2, 2.3 CMU/SEI-2010-TN-028 24

NIST SP 800-53 Rev. 3 Taxonomy Subclasses and Elements Control Number Control Description SC-33 Transmission Preparation Integrity 1.1, 1.2, 2.1, 2.2, 2.3 SC-34 Non-Modifiable Executable Programs 1.1, 1.2, 2.1, 2.2, 2.3 SI-1 System and Information Integrity Policy and Procedures 1.1, 1.2, 2.2, 2.3, 3.1, 3.2 SI-2 Flaw Remediation 1.1, 1.2, 2.2, 2.3, 3.1, 3.2 SI-3 Malicious Code Protection 1.1, 1.2, 2.2, 2.3, 3.1, 3.2 SI-4 Information System Monitoring 1.1, 1.2, 2.2, 2.3, 3.1, 3.2 SI-5 Security Alerts, Advisories, and Directives 1.1, 1.2, 2.2, 2.3, 3.1, 3.2 SI-6 Security Functionality Verification 1.1, 1.2, 2.2, 2.3, 3.1, 3.2 SI-7 Software and Information Integrity 1.1, 1.2, 2.2, 2.3, 3.1, 3.2 SI-8 Spam Protection 1.1, 1.2, 2.2, 2.3, 3.1, 3.2 SI-9 Information Input Restrictions 1.1, 1.2, 2.2, 2.3, 3.1, 3.2 SI-10 Information Input Validation 1.1, 1.2, 2.2, 2.3, 3.1, 3.2 SI-11 Error Handling 1.1, 1.2, 2.2, 2.3, 3.1, 3.2 SI-12 Information Output Handling and Retention 1.1, 1.2, 2.2, 2.3, 3.1, 3.2, 4.2 SI-13 Predictable Failure Prevention 1.1, 1.2, 2.2, 2.3, 3.1, 3.2 PM-1 Information Security Program Plan 3.1, 3.2, 3.3 PM-2 Senior Information Security Officer 3.1, 3.2, 3.3 PM-3 Information Security Resources 3.1, 3.2, 3.3 PM-4 Plan of Action and Milestones Process 3.1, 3.2, 3.3 PM-5 Information System Inventory 3.1, 3.2, 3.3 PM-6 Information Security Measures of Performance 3.1, 3.2, 3.3 PM-7 Enterprise Architecture 3.1, 3.2, 3.3 PM-8 Critical Infrastructure Plan 3.1, 3.2, 3.3 PM-9 Risk Management Strategy 3.1, 3.2, 3.3 CMU/SEI-2010-TN-028 25

NIST SP 800-53 Rev. 3 Taxonomy Subclasses and Elements Control Number Control Description PM-10 Security Authorization Process 3.1, 3.2, 3.3 PM-11 Mission/Business Process Definition 3.1, 3.2, 3.3 CMU/SEI-2010-TN-028 26

Appendix B: Mapping of Selected Taxonomy Subclasses and Elements to NIST SP 800-53 Rev. 3 Controls The following table can be used to determine which NIST controls to consider in order to mitigate a specific operational cyber security risks. Table 3: Mapping of Taxonomy Subclasses and Elements to NIST Controls Taxonomy Class, Subclass, Element NIST SP 800-53 Rev. 3 Controls 1 Actions of People 1.1 Inadvertent 1.1.1 Mistakes 1.1.2 Errors 1.1.3 Omissions 1.2 Deliberate 1.2.1 Fraud 1.2.2 Sabotage 1.2.3 Theft 1.2.4 Vandalism AC 2-6, 16, 19-22 AU 1-3, 5, 9-10 CA 1-3 CM 5, 7 IA 1-8 IR 1, 3-8 MA 2-6 MP 1-6 PE 1-19 PL 4 PS 1-8 RA 5 SC 1-34 SI 1-13 AC 2, 5-6, 16-18, 19-22 AT 4 AU 1-3, 5, 9-10 CA 1-3 CM 5, 7 CP 2 IA 1-8 IR 1, 3-8 MP 1-6 PE 1-19 PL 4 PS 1-8 RA 5 SC 1-34 SI 1-13 CMU/SEI-2010-TN-028 27

Taxonomy Class, Subclass, Element NIST SP 800-53 Rev. 3 Controls 1.3 Inaction 1.3.1 Skills 1.3.2 Knowledge 1.3.3 Guidance CA 5 CP 2-4 IR 1-8 MA 2-6 PL 4 PS 1-8 RA 5 AT 3, 5 AT 2, 5 AT 2, 3 1.3.4 Availability 2 Systems and Technology Failures 2.1 Hardware 2.1.1 Capacity 2.1.2 Performance 2.1.3 Maintenance AC 17, 18, 19 CM 8 CP 6, 7 IA 3 MP 1-6 PE 1-19 SA 2, 3, 5-14 SC 1-34 AU 4 MA 1-6 2.1.4 Obsolescence 2.2 Software 2.2.1 Compatibility 2.2.2 Configuration Management 2.2.3 Change Control 2.2.4 Security Settings AC 3, 4, 7-11, 17, 18, 19 AU 7-10, 12, 14 CA 5, 7 CM 7, 8 CP 6-9 IA 1, 2, 4-8 MP 1-6 SA 2, 3, 5-14 SC 1-34 SI 1-13 AC 2, 5, 6 CM 1-6, 9 AC 2, 5, 6 CM 1-6 AC 5, 6 CM 1-6 RA 5 2.2.5 Coding Practices 2.2.6 Testing CM 4, 5 CMU/SEI-2010-TN-028 28

Taxonomy Class, Subclass, Element NIST SP 800-53 Rev. 3 Controls 2.3 Systems 2.3.1 Design 2.3.2 Specifications 2.3.3 Integration AC 3, 4, 7-11, 16 AU 7-10, 12, 14 CA 7 CM 7-9 CP 7-9 IA 1-8 MA 1-6 SA 1-14 SC 1-34 SI 1-13 AC 5, 6 2.3.4 Complexity 3 Failed Internal Processes 3.1 Process Design and/or Execution 3.1.1 Process Flow 3.1.2 Process Documentation 3.1.3 Roles and Responsibilities 3.1.4 Notifications and Alerts AC 1, 5, 6, 14, 16-22 AT 1-4 AU 2, 3, 7, 9-13 CA 1-3, 5, 6 CM 1-8 CP 1, 4, 9, 10 IA 1-8 IR 1, 3-8 MA 1-6 MP 1-6 PE 1-19 PL 1, 2, 6 RA 1-3, 5 SI 1-13 PM 1-11 3.1.5 Information Flow 3.1.6 Escalation of Issues 3.1.7 Service Level Agreements 3.1.8 Task Hand-Off CMU/SEI-2010-TN-028 29

Taxonomy Class, Subclass, Element 3.2 Process Controls 3.2.1 Status Monitoring 3.2.2 Metrics 3.2.3 Periodic Review 3.2.4 Process Ownership 3.3 Supporting Processes 3.3.1 Staffing NIST SP 800-53 Rev. 3 Controls AC 5, 6, 14, 17, 18, 21 AU 1-3, 6, 9-11, 13 CA 1, 2, 5-7 CM 1-3, 6, 7 CP 1 IA 2-8 IR 1, 3-8 MA 1-6 MP 1-6 PE 1-19 PL 1, 2, 6 RA 1-3, 5 SI 1-13 PM 1-11 CA 5 CP 2, 8 MA 2-6 PL 1, 2, 6 SA 2, 3, 5-14 PM 1-11 3.3.2 Funding 3.3.3 Training and Development 3.3.4 Procurement AC 21, 22 AT 1-4 CP 3, 4 IR 2 PL 4 PS 1-8 AC 20 IR 7 SA 1, 4 4 External Events 4.1 Hazards AT 3 CP 1-4, 6-8, 10 PE 10-12, 16-18 4.1.1 Weather Event 4.1.2 Fire 4.1.3 Flood PE 13 PE 15 4.1.4 Earthquake 4.1.5 Unrest 4.1.6 Pandemic CMU/SEI-2010-TN-028 30

Taxonomy Class, Subclass, Element 4.2 Legal Issues 4.2.1 Regulatory compliance 4.2.2 Legislation 4.2.3 Litigation 4.3 Business Issues 4.3.1 Supplier Failure 4.3.2 Market Conditions NIST SP 800-53 Rev. 3 Controls AC 19 AU 13 CP 2, 4, 8, 10 IA 8 IR 6 MP 1-6 PE 19 PL 5 PS 1-6, 8 RA 2, 3 SA 2, 3, 5-14 SI 12 AC 20 CP 1, 2, 4, 6, 8, 10 IA 8 MA 5 PL 5 PS 7 RA 2, 3 SA 2, 3, 5-14 AU 1, 2 AU 1, 2 4.3.3 Economic Conditions 4.4 Service Dependencies CP 1-4, 7 PE 10-13, 15-18 SA 1, 4 4.4. Utilities 4.4.2 Emergency services 4.4.3 Fuel 4.4.4 Transportation CMU/SEI-2010-TN-028 31

CMU/SEI-2010-TN-028 32

References URLs are valid as of the publication date of this document. [Alberts 2001a] Alberts, Christopher & Dorofee, Audrey. Operationally Critical Threat, Asset, and Vulnerability Evaluation (OCTAVE) Method Implementation Guide, v2.0. Software Engineering Institute, Carnegie Mellon University, 2001. http://www.cert.org/octave/ [Alberts 2001b] Alberts, Christopher & Dorofee, Audrey. OCTAVE Threat Profiles. Software Engineering Institute, Carnegie Mellon University, 2001. http://www.cert.org/archive/pdf/octavethreatprofiles.pdf [BIS 2006] Bank for International Settlements (BIS). International Convergence of Capital Measurement and Capital Standards: A Revised Framework Comprehensive Version. http://www.bis.org/publ/bcbs128.pdf (2006). [Caralli 2010a] Caralli, Richard A.; Allen, Julia H.; Curtis, Pamela D.; White, David W.; & Young, Lisa R. CERT Resilience Management Model, v1.0 (CMU/SEI-2010-TR-012). Software Engineering Institute, Carnegie Mellon University, 2010. http://www.sei.cmu.edu/library/abstracts/reports/10tr012.cfm [Caralli 2010b] Caralli, Richard A.; Allen, Julia H.; Curtis, Pamela D.; White, David W.; & Young, Lisa R. CERT Resilience Management Model, v1.0 - Risk Management (RISK). Software Engineering Institute, Carnegie Mellon University, 2010. http://www.cert.org/resilience/rmm.html [DHS 2008] Department of Homeland Security (DHS) Risk Steering Committee. DHS Risk Lexicon. Department of Homeland Security, September 2008. http://www.dhs.gov/xlibrary/assets/dhs_risk_lexicon.pdf [FISMA 2002] Federal Information Systems Management Act of 2002, 44 U.S.C. 3542(b)(1). Office of the Law Revision Counsel, 2002. http://uscode.house.gov/download/pls/44c35.txt [Gallagher 2005] Gallagher, Brian P.; Case, Pamela J.; Creel, Rita C.; Kushner, Susan; & Williams, Ray C. A Taxonomy of Operational Risks (CMU/SEI-2005-TN-036). Software Engineering Institute, Carnegie Mellon University, 2005. http://www.sei.cmu.edu/library/abstracts/reports/05tn036.cfm CMU/SEI-2010-TN-028 33

[Kendall 2007] Kendall, Richard P.; Post, Douglass E.; Carver, Jeffrey C.; Henderson, Dale B.; & Fisher, David A. A Proposed Taxonomy for Software Development Risks for High-Performance Computing (HPC) Scientific/Engineering Applications (CMU/SEI-2006-TN-039). Software Engineering Institute, Carnegie Mellon University, 2007. http://www.sei.cmu.edu/library/abstracts/reports/06tn039.cfm [NIST 2009] National Institute of Standards and Technology. Recommended Security Controls for Federal Information Systems and Organizations (NIST Special Publication 800-53, Revision 3). U.S. Department of Commerce, 2009. http://csrc.nist.gov/publications/nistpubs/800-53-rev3/ sp800-53-rev3-final_updated-errata_05-01-2010.pdf CMU/SEI-2010-TN-028 34

REPORT DOCUMENTATION PAGE Form Approved OMB No. 0704-0188 Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden, to Washington Headquarters Services, Directorate for information Operations and Reports, 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302, and to the Office of Management and Budget, Paperwork Reduction Project (0704-0188), Washington, DC 20503. 1. AGENCY USE ONLY (Leave Blank) 2. REPORT DATE December 2010 3. REPORT TYPE AND DATES COVERED Final 4. TITLE AND SUBTITLE 5. FUNDING NUMBERS A Taxonomy of Operational Cyber Security Risks FA8721-05-C-0003 6. AUTHOR(S) James J. Cebula, Lisa R. Young 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) Software Engineering Institute Carnegie Mellon University Pittsburgh, PA 15213 9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) HQ ESC/XPK 5 Eglin Street Hanscom AFB, MA 01731-2116 11. SUPPLEMENTARY NOTES 8. PERFORMING ORGANIZATION REPORT NUMBER CMU/SEI-2010-TN-028 10. SPONSORING/MONITORING AGENCY REPORT NUMBER 12A DISTRIBUTION/AVAILABILITY STATEMENT 12B DISTRIBUTION CODE Unclassified/Unlimited, DTIC, NTIS 13. ABSTRACT (MAXIMUM 200 WORDS) This report presents a taxonomy of operational cyber security risks that attempts to identify and organize the sources of operational cyber security risk into four classes: (1) actions of people, (2) systems and technology failures, (3) failed internal processes, and (4) external events. Each class is broken down into subclasses, which are described by their elements. This report discusses the harmonization of the taxonomy with other risk and security activities, particularly those described by the Federal Information Security Management Act (FISMA), the National Institute of Standards and Technology (NIST) Special Publications, and the CERT Operationally Critical Threat, Asset, and Vulnerability Evaluation SM (OCTAVE ) method. 14. SUBJECT TERMS 15. NUMBER OF PAGES taxonomy, operational risk, FISMA, NIST, cyber security, OCTAVE, resilience 47 16. PRICE CODE 17. SECURITY CLASSIFICATION OF REPORT Unclassified 18. SECURITY CLASSIFICATION OF THIS PAGE Unclassified 19. SECURITY CLASSIFICATION OF ABSTRACT Unclassified 20. LIMITATION OF ABSTRACT UL NSN 7540-01-280-5500 Standard Form 298 (Rev. 2-89) Prescribed by ANSI Std. Z39-18 298-102